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Thanh, Pham-Duy,Vu-Van, Hiep,Koo, Insoo Hindawi Limited 2018 Security and communication networks Vol.2018 No.-
<P>We study jamming attacks in the physical layer of multihop cognitive radio networks (MHCRNs) where energy-constrained relays forward information from the source to the destination. Meanwhile, a jammer can transmit interfering signals on a channel such that all ongoing transmissions on this channel will be corrupted. In this paper, all jammers can attack only one of the predefined channels in each time slot. Moreover, they can randomly switch channels to start jamming another channel at the beginning of every time slot. The switching behavior is assumed to follow a Gaussian distribution. Due to limited battery capacity in the relays, energy harvesting is utilized to solve the energy-constrained problem in the cognitive radio network. Subsequently, relays are able to harvest energy from non-radio frequency (non-RF) signals such as solar, wind, or temperature. In this paper, we determine the throughput/delay ratio as a key metric to evaluate the performance in MHCRNs. Owing to the limited battery capacity in the relays and the jamming problem, the source needs to select proper relays and channels for each data transmission frame to optimize overall network performance in terms of end-to-end delay, throughput, and energy efficiency. Therefore, we provide two novel multihop allocation schemes to maximize achievable end-to-end throughput while minimizing delay in the presence of jammers. Through simulation results, we validate the effectiveness of the proposed schemes under multiple jamming attacks in MHCRNs.</P>
Quang Vang DANG(Quang Vang DANG ),Viet Thanh Truc TRAN(Viet Thanh Truc TRAN ),Hieu PHAM(Hieu PHAM ),Van Nam MAI(Van Nam MAI ),Quoc Duy VUONG(Quoc Duy VUONG ) 한국유통과학회 2023 The Journal of Asian Finance, Economics and Busine Vol.10 No.2
This paper investigates the determinants of credit accessibility and the effect of credit on the income of farm households borrowing from Vietnam Bank for Agriculture and Rural Development, Giong Rieng District Branch, Kien Giang Province. Based on the primary data of 200 farming households who are the customer of the bank, the study applied the Probit regression model to examine determinant factors of credit accessibility of farm households and employed the Propensity score matching method to investigate the impact of credit on households’ income. The findings of the Probit regression shown that three independent variables that significantly influence the access to credit of households are household size, income source, and farm size. Besides that, the Propensity score matching method results showed a difference of 23.799 million VND/year between the income of borrowing households and that of non-borrowing households at the significance level of 1%. The difference in the imcome from the interval and central matching methods are VND 24.700 million VND/year and VND 24.633 million VND/year, respectively. Given empirical findings suggetsted that several recommendations to increase the credit accessibility of farm households, thereby creating favorable conditions for improving their income.
Duy Le Nguyen,Hieu Le-Trung Hoang,Vu Ngoc-Anh Ho,Toan Duong Pham,Nam Thanh Nguyen,Van Thi-Thu Tran,Tuong Manh Ho,Lan Ngoc Vuong The Korean Society for Reproductive Medicine 2024 Clinical and Experimental Reproductive Medicine Vol.51 No.1
Objective: The purpose of this study was to identify factors associated with twin pregnancy following day 3 double embryo transfer (DET). Methods: This retrospective cohort study incorporated data from 16,972 day 3 DET cycles. The participants were women aged between 18 and 45 years who underwent in vitro fertilization with intracytoplasmic sperm injection (IVF/ICSI) at My Duc Assisted Reproduction Technique Unit (IVFMD), My Duc Hospital, located in Ho Chi Minh City, Vietnam. Results: Of the 16,972 day 3 DET cycles investigated, 8,812 (51.9%) resulted in pregnancy. Of these, 6,108 cycles led to clinical pregnancy, with 1,543 (25.3% of clinical pregnancies) being twin pregnancies. Factors associated with twin pregnancy included age under 35 years (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.32 to 1.71; p<0.001) and cycles involving the transfer of at least one grade I embryo. Relative to the transfer of two grade III embryos, the risk of twin pregnancy was significantly elevated following the transfer of two grade I embryos (OR, 1.40; 95% CI, 1.16 to 1.69; p<0.001) or a combination of one grade I and one grade II embryo (OR, 1.27; 95% CI, 1.05 to 1.55; p=0.001). Conclusion: By analyzing a large number of IVF/ICSI cycles, we identified several predictors of twin pregnancy. These findings can assist medical professionals in tailoring treatment strategies for couples with infertility.
A dense, pinholes-free pure cubic phase CsPbBr3 nanocrystals film for high-performance photodetector
Thanh-Tung Duong,Phuong-Nam Tran,Tuan-Pham Van,Duy-Hung Nguyen,Van-Dang Tran 대한금속·재료학회 2024 ELECTRONIC MATERIALS LETTERS Vol.20 No.2
This study demonstrates a simple centrifugal coating method to prepare high-quality pure cubic phase CsPbBr 3 nanocrystalfi lm. The resultant perovskite layers possess a uniform and dense 500 nm-thick, with a bandgap of 2.38 eV, a low trap-statedensity of 6.9 × 10 − 15 cm − 3 , and carrier mobility of approximately 19.8 cm 2 V − 1 s − 1 . Furthermore, CsPbBr 3 NCs-basedself-powered photodetectors with high charge carriers’ charge transfer are fabricated. The device shows a low dark currentdensity of 1.93 × 10 − 7 A/cm 2 at room temperature. Such photodetectors show the highest responsivity of 3.0 AW − 1 ,specifi c detectivity of 1.2 × 10 13 Jones, and external quantum effi ciency (EQE) of 920% at zero bias voltage. The proposedmethod shows signifi cant promise for use in the lab fabrication of optoelectronic devices based on thin fi lms of nanocrystalperovskite materials.
Thanh Khiem Nguyen,Ham Hoi Nguyen,Tuan Hiep Luong,Kim Khue Dang,Van Duy Le,Duc Dung Tran,Van Minh Do,Hong Quang Pham,Hoan My Pham,Thi Lan Tran,Cuong Thinh Nguyen,Hong Son Trinh,Yosuke Inoue 한국간담췌외과학회 2024 Annals of hepato-biliary-pancreatic surgery Vol.28 No.1
Backgrounds/Aims: Pancreaticoduodenectomy (PD) is the only radical treatment for periampullary malignancies. Superior mesenteric artery (SMA) first approach combined with total meso-pancreas (MP) excision was conducted to improve the oncological results. There has not been any previous research of a technique that combines the SMA first approach and total MP excision with a detailed description of the MP macroscopical shape. Methods: We prospectively assessed 77 patients with periampullary malignancies between October 2020 and March 2022 (18 months). All patients had undergone PD with SMA first approach combined total MP excision. The perioperative indications, clinical data, intra-operative index, R0 resection rate of postoperative pathological specimens (especially mesopancreatic margin), postoperative complications, and follow-up results were evaluated. Results: The median operative time was 289.6 min (178−540 min), the median intraoperative blood loss was 209 mL (30−1,600 mL). Microscopically, there were 19 (24.7%) cases with metastatic MP, and five cases (6.5%) with R1-resection of the MP. The number of lymph nodes (LNs) harvested and metastatic LNs were 27.2 (maximum was 74) and 1.8 (maximum was 16), respectively. Some (46.8%) patients had pancreatic fistula, but mostly in grade A, with 7 patients (9.1%) who required re-operations. Some 18.2% of cases developed postoperative refractory diarrhea. The rate of in-hospital mortality was 1.3%. Conclusions: The PD with SMA first approach combined TMpE for periampullary malignancies was effective in achieving superior oncological statistics (rate of MP R0-resection and number of total resected LNs) with non-inferior short-term outcomes. It is necessary to evaluate survival outcomes with long-term follow-up.
Nguyen Ngoc Duy,Latsamy Xayavong,Nguyen Kim Uyen,Vinh Nguyen Thanh Pham,Tran Viet Nhan Hao 한국물리학회 2019 새물리 Vol.69 No.10
Nuclear physics is an obligatory subject for the general physics program of undergraduates in most of the natural science universities worldwide. In nuclear physics, the shell model is one of the most important models, and is well used to determine the spin-parity and the magnetic moment of a nucleus. Over ten years of teaching general physics, we have realize that most undergraduate students find calculating these parameters by using this shell model to be difficult due to the classification of the subshells and the intrinsic spin of nucleons. With the hope to help these students, in the present study, we introduce a graphical-user-interface (GUI) program to execute our selfdeveloped Shell Model Calculator (SMC) code written in the Visual Basic 6.0 (VB6) programming language. Our SMC validation results for the quantum quantities in a series of nuclei Z = 1 - 20 were compared with experimental data and found to be in good agreement. In general, we successfully developed an SMC program that can be used for teaching, learning, and researching nuclear physics in universities.
Van-Hoang Tran,Thanh-Huan Nguyen,Frédéric Plourde,Khanh-Duy Cong Do,Duy-Hung Chung,Cong-Truong Dinh,Gia-Diem Pham 한국유체기계학회 2023 International journal of fluid machinery and syste Vol.16 No.2
In order to increase turbine efficiency while retaining structural integrity, modern jet engines need an effective cooling system. Pin-fin arrays play a significant role in the internal cooling system of the turbine blade. In examining the efficacy of cooling techniques using pin-fins, the other papers focus on pin-fin configurations. In contrast, the current study is a step toward optimizing cooling cascade endwalls for better maneuvering and reservation of vortices, which leads to more considerable heat transfer near the endwalls. This study examines the flow field and heat transfer of roughed endwall in the pin-fin channel, including varieties with flat endwall and extruded endwall. The heat transfer of the channel and pressure drop properties of the extruded endwall case are quantitatively assessed to contrast with those of the flat endwalls scenario for an intake Reynolds number range of 7400 to 36000. The leading and trailing surfaces of the channel are divided into five streamwise regions to understand better how well the pin-fins and endwalls transmit heat. The results show that the new endwall construction significantly increases the high heat transfer zones around the pin-fins compared to the flat endwall scenario. In the meantime, the heat transfer of the channel to the pin-fins is enhanced by the modified endwall configuration. The redesigned endwall outperformed the basic case regarding the HTEI, rising by 15.9%. It is found that the friction factor of the new design is increased due to the narrowing channel. However, due to their much higher heat transfer capacity, the HTEI of extruded endwall is up to 41.5% higher than the HTEI of the channel with flat endwalls. These results demonstrate that the heat transfer properties of pin-fins can be significantly improved by optimizing endwall design.